can someone educate me on the 340 6pk parts

I just picked up a edelbrock chrysler small block 6 pack intake with two carbs. Im missing the center carbs. I beleive this is all stock 340 6pk parts. Origionally i thought about using the setup on my dart but i really dont want to go away from my 340 dual scoop hood. So kinda thinking about selling/trading this toward some edelbrock heads to fund my 340 build. Is there anyway to find a value or identify the part numbers to what this was origionally on?? should i find a center carb or sell without??? Any help would be appreciated.
thanks
mark